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The next component in canning is the acid level, or pH. Foods that are high in acid (acidic) call for different (some might say easier) means of preservation than foods that are low in acid (alkaline). See the table “Acidity and Safe Food Preservation” for some specific fruits and vegetables, but as a rule of thumb, fruits (including tomatoes) are high in acid while vegetables and meats are low in acid. Acidity is measured on a scale of pH values from 1 to 14, with 1 being the most acidic and 14 being the most alkaline. The midpoint on that scale (7) is neutral, but for our purposes, the tipping point is a pH level of 4.6. Thus, if a food has a pH value of 4.7 or higher, it will require different processing than foods that are 4.6 or lower. Note: Foods with a pH value of 4.7 or higher cannot be safely processed in a water-bath canner.

ACIDITY AND SAFE FOOD PRESERVATION

TYPE OF SPOILAGE AGENT	MAXIMUM PH LEVEL THAT AN ORGANISM WILL SUSTAIN	TYPE OF FOOD	METHOD OF CANNING
	1 (Strongly Acidic)
Molds	2
Yeasts	3	LemonsPicklesApricotsPlumsApplesPeachesSauerkrautPears	High-Acid Foods:safe to processat 212°F in awater-bath canner
	4	Tomatoes
Bacteria	4.6		Highest pH level that is safe to water-bath
	5	FigsOkraCarrotsBeetsGreen BeansSpinach	Low-Acid Foods:safe to processat 240°F in apressure canner
	6
	7	Corn
		Peas
	14 (Strongly Alkaline)

TAKE BABY STEPS

When you try a new recipe, start small. Even recipes from reliable sources may not work out as well as you’d hoped. Just as you’ve tried recipes from great cookbooks and find that you simply don’t like the way a recipe tastes, or that it doesn’t look like the picture, the same can be true for any of the recipes involving food preservation. First time around, make just one batch. You’ve heard this before, but it’s worth repeating: if you are a novice, start simply. Try water-bath canning or freezing. Freezing green beans is a snap (pun intended) and the results are great! Canning tomatoes or peaches is easy. Making strawberry freezer jam is even easier, but cooked jam is a breeze, too. You’ll find recipes for these in the following chapters. Yes, it’s tempting to want to triple the recipe or try something exotic. But starting small and simple helps you to quickly find what works best for you, and then grow your new skills with confidence.